Allen Ginsberg/Corbis, via Magnolia Pictures

“Magic Trip: Ken Kesey’s Search for a Kool Place,” a film by Alex Gibney and Alison Ellwood that opens on Friday, is an exercise in what they call “archival vérité.”

It’s a documentary that uses old footage to recreate a documentary that Kesey intended to make about his 1964 cross-country bus trip - the one so memorably chronicled in Tom Wolfe’s account, “The Electric Kool-Aid Acid Test.”

In all Kesey and the Merry Pranksters, as his crew called themselves, shot some 40 hours of 16-millimeter film, but the project was never really finished. As Mr. Wolfe wrote, “Plunging in on those miles of bouncing, ricocheting, blazing film with a splicer was like entering a jungle where the greeny vines grew faster than you could chop them down in front of you.”

Kesey showed all 40 hours unedited a couple of times and also hacked the footage up into various shorter versions before stowing the film cans in his barn, near Eugene, Ore., where they rusted away - until Mr. Gibney and Ms. Ellwood showed up.